You might notice that some invoice totals are slightly different, often by just 1 cent. This can mean that numbers don't tally, especially if the same services or products were previously invoicing at a round amount.
These small differences are expected and are caused by how rounding is applied during tax and price calculations. Different calculation methods round values at different stages (for example, per item vs the invoice total), which can result in tiny changes to the final amount.
This can occur in a few common situations:
Switching between tax calculation methods (i.e. from tax-inclusive to tax-exclusive)
Invoices that include multiple quantities of the same billable item or when adding quantities with decimals
Invoices with several taxable items, where rounding is applied across each line
Even though the difference is small, it can show up on the final invoice total and mean that patients pay an unexpected amount.
A common scenario
Here's an example of how this can happen when switching tax calculation methods:
Let's say you have a billable item with a base price that ultimately comes to $80 including tax.
If your tax calculation method is tax-inclusive, when adding this billable item to an invoice, the $80 is treated as the final price, and tax is broken down as a separate section at the end
If the tax calculation method is changed to tax-exclusive, the same billable item will have the pre-tax price calculated and have tax added on top of that. Rounding is applied at each step. Because of the differences in the order of calculations, the same billable item now appears with different rounded values, resulting in an invoice total of $80.01 instead of $80.
Nothing is set up incorrectly. The difference comes from the order in which rounding is applied. Where tax-inclusive pricing rounds the final total, tax-exclusive pricing may round at the unit price or tax line level. This behaviour is expected when switching tax calculation methods.
How to handle rounding differences
There are a couple of ways to deal with these small differences, depending on your setup and reporting needs.
Option 1: Review and adjust your prices
If you want future invoices to land on a specific total, it can help to test and fine-tune your pricing first.
Create a "test" invoice and add the relevant billable item or product
Adjust the unit price on the invoice until the final total calculates to the correct amount
Once you’re happy with the result, head to Settings → Finances → Billable items to review your service prices
Check the Products tab for any products you sell
Update the unit price to match what you confirmed in the test invoice, so new invoices calculate the way you expect
This approach is especially useful if you want consistent totals across invoices without needing manual adjustments later. If you need to update your prices in bulk, check out this guide.
Option 2: Use a rounding adjustment item
If the difference only occurs on certain invoices (for example, due to quantities or tax rounding), you can balance the invoice using a small adjustment line.
Create a billable item called something like “Rounding adjustment”
Set the price to +0.01 or –0.01 as needed
Add it to the invoice to bring the total to the desired amount
This can help ensure accounting accuracy and keep invoice totals aligned without changing your standard pricing.
You can use either (or both) of these options to make sure your prices match what you want your patients to be charged or what gets sent to insurers.
Invoices that have already been raised will not be altered. Only new invoices created after you change tax calculation methods will use the new calculation.
Reviewing your pricing or using a rounding adjustment can help keep invoice totals consistent with your expectations and reporting needs. If you have more questions about how rounding happens, get in touch with our support team! 💬